package controller;

import com.fasterxml.jackson.databind.ObjectMapper;
import model.User;
import model.UserDao;
import utils.BaseContext;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;

@WebServlet("/login")
public class LoginServlet extends HttpServlet {
    private ObjectMapper objectMapper=new ObjectMapper();
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("utf8");
        resp.setCharacterEncoding("utf8");
        //1.获取到请求中的参数
        String username=req.getParameter("username");
        String password=req.getParameter("password");
        //进行校验
        if (username==null || "".equals(username)||password==null||"".equals(password)){
            //请求内容缺失，登录失败~
            resp.setContentType("text/html;charset=utf8");
            resp.getWriter().write("当前的用户名或密码为空！");
            return;
        }
        //2.和数据库中的内容进行比较
        UserDao userDao=new UserDao();
        User user=userDao.selectByName(username);
        if (user==null || !user.getPassword().equals(password)){
            //登录失败
            resp.setContentType("text/html;charset=utf8");
            resp.getWriter().write("用户名或密码错误！");
            return;
        }
        //3.如果比较通过，则创建会话
        HttpSession session=req.getSession(true);
        //把刚才的用户信息，加到会话中
        session.setAttribute("user",user);
        // 登录成功，存入threadlocal
        Long userId= (long) user.getUserId();
        BaseContext.setCurrentUserId(userId);
        //4.返回一个重定向报文，跳转到博客列表页
        resp.sendRedirect("blog_list.jsp");//302
    }

    //这个方法用来让前面的前端检测当前的登录状态
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setContentType("application/json;charset=utf8");
        HttpSession session=req.getSession(false);
        if (session==null){
            //检测会话是否存在，不存在说明未登录！
            User user=new User();
            resp.getWriter().write(objectMapper.writeValueAsString(user));
            return;
        }
        User user=(User)session.getAttribute("user");
        if (user==null){
            //会话虽然存在，但是会话这里没有user对象，也视为未登录
            user=new User();
            resp.getWriter().write(objectMapper.writeValueAsString(user));
            return;
        }
        //已经是登录的状态！
        //注意，此处的密码不能返回给前端
        user.setPassword("");
        resp.getWriter().write(objectMapper.writeValueAsString(user));
    }
}
